With a fast development of touch display screens, current mainstream products are all employed with a structure design of an Add-on touch screen. However, the conventional Add-on touch screen is very bulky and costly. With requirement for a thin display by consumers, a In-Cell liquid crystal screen has become an important development direction in the touch display field.
In-Cell refers to a method for incorporating the function of the touch panel into a pixel circuit of a liquid crystal pixel, that is, for incorporating the touch sensor function into a liquid crystal cell, which can make the screen thinner. The current In-Cell touch display screen generally employs a capacitor sensing technology. In particular, a touch driving electrode (a Tx electrode) and a sensing electrode (a Rx electrode) manufactured for achieving the touch function are arranged in the liquid crystal cell. The Tx electrode and the Rx electrode are vertical with each other, wherein the Tx electrode is controlled by a touch control chip and outputs a series of rectangular waves line by line sequentially, and the Rx electrode will be set up with a DC voltage value as a receiving terminal. When no finger is touching the liquid crystal screen and the Tx electrode is outputting a pulse, the capacitive coupling between the Rx electrode and the Tx electrode in an overlapped region of the Tx electrode and the Rx electrode as well as a region adjacent to the overlapped region will make a voltage of the Rx electrode fluctuate, and at this time, the touch control chip will consider the fluctuation as belonging to a case in which there is no touch. When a finger is touching the liquid crystal screen, a capacitor will be formed between the finger and the Tx electrode as well as between the finger and the Rx electrode. When the Tx electrode is outputting the pulse, the coupling situation between the Rx electrode and the Tx electrode will vary due to the above capacitor, so that the voltage fluctuation situation at the Rx electrode is different from that when there is no finger touching. The touch control chip determines such difference by an algorithm to achieve the purpose for detecting the touched location.
In the In-Cell touch display screen, in order to increase the sensitivity of the touch detection, the Rx electrode is generally arranged on a color filter substrate close to the liquid crystal screen, and the backside of the color filter substrate (a side away from the liquid crystal) is further arranged with a grounded transparent conductive layer (an anti-static layer) for decreasing the static effect on the display effect of the liquid crystal panel. The inventors found that the anti-static layer will prevent the touch function from being realized, and affect the sensitivity of the touch control. However, if the anti-static layer is removed, the capability of bearing the static by the liquid crystal panel will be decreased to a large extent.